Novel Balanced Chromosome Abnormalities Found in Autism

FRIDAY, April 20 (HealthDay News) -- New genetic variants associated with balanced alterations of chromosome structure have been identified in individuals with autism and related neurodevelopmental disorders, many of which are also present in individuals with schizophrenia, according to a study published online April 19 in Cell.

Michael E. Talkowski, Ph.D., from Massachusetts General Hospital in Boston, and colleagues sequenced balanced chromosomal abnormalities (genomic structural variants that do not involve large gains and losses of genetic material) in 38 individuals with autism or related neurodevelopmental disorders.

The researchers found disruptions in 33 loci, with a large increase in copy number variants seen in these loci among neurodevelopmental cases. The loci comprised four categories: genes previously implicated in neurodevelopment; genes contributing to microdeletion syndromes (which contribute to neurodevelopmental and psychiatric disorders); novel genes likely involved in neurodevelopment (22 genes); and genes previously implicated in later-onset psychiatric disorders. Analysis of previous genome-wide association studies of autism and schizophrenia showed that many of these risk-associated genes were enriched in those studies.

"Our findings suggest a polygenic risk model of autism and reveal that some neurodevelopmental genes are sensitive to perturbation by multiple mutational mechanisms, leading to variable phenotypic outcomes that manifest at different life stages," Talkowski and colleagues conclude.

Several authors are employees of Signature Genomic Laboratories, PerkinElmer Inc.